YouTube API: Delete video HTTP request from Ruby not working - ruby-on-rails

Question

I am trying to delete a video on YouTube from a Ruby on Rails application. I am following these instructions, from the YouTube API docs:
DELETE /feeds/api/users/default/uploads/VIDEO_ID HTTP/1.1
Host: gdata.youtube.com
Content-Type: application/atom+xml
Authorization: Bearer ACCESS_TOKEN
GData-Version: 2
X-GData-Key: key=DEVELOPER_KEY
I am not very familiar with Ruby's Net::HTTP class, but it seems that no matter what I try I cannot get the request to work properly. I have looked carefully at the many other StackOverflow questions regarding deleting videos from YouTube, but none that I could find address this particular problem. My code is below, where I've replaced the user name, video ID, access token, and developer key.
url = URI.parse("https://gdata.youtube.com/feeds/api/users/[USER_NAME]/uploads/[VIDEO_ID]")
post_args = { 'Host' => 'gdata.youtube.com', 'GData-Version' => '2', 'Content-Type' => 'application/atom+xml', 'Authorization' => "Bearer [ACCESS_TOKEN]", 'X-GData-Key' => 'key=[DEVELOPER_KEY]' }
req = Net::HTTP::Delete.new(url.path)
req.set_form_data(post_args)
httpreq = Net::HTTP.new(url.host, url.port)
httpreq.use_ssl = true
resp = httpreq.start {|http| http.request(req) }
Checking the response, I get an Error 400 (Bad Request) from YouTube. The response simply says "Your client has issued a malformed or illegal request. That's all we know".
Is there something wrong with the request I'm making? I've checked it against the template time and time again and I can't see anything wrong with it. I know that my access token and developer key are working because I can make other requests like video uploads just fine.
I printed the debug output from the HTTP request, and as far as I can tell it looks fine:
<- "DELETE /feeds/api/users/[USER_NAME]/uploads/[VIDEO_ID] HTTP/1.1\r\nAccept: */*\r\nUser-Agent: Ruby\r\nContent-Type: application/x-www-form-urlencoded\r\nHost: gdata.youtube.com\r\nContent-Length: 275\r\n\r\n"
<- "Host=gdata.youtube.com&GData-Version=2&Content-Type=application%2Fatom%2Bxml&Authorization=Bearer+[ACCESS_TOKEN]&X-GData-Key=key%3D[DEVELOPER_KEY]"
The only thing I could see as a possible problem was that in the first line of the request, the "Content-Type" is set to "application/x-www-form-urlencoded". Again, not being an expert on HTTP requests I'm not sure what the difference is between the Content-Type set in the first line and the Content-Type that I explicitly set as "application/atom+xml" which appears on the second line of the request. After some digging, though, I found out that the set_form_data method automatically sets the content type as "application/x-www-form-urlencoded", so I tried adding the following line to my code:
req.content_type = 'application/atom+xml'
right after the line
req.set_form_data(post_args)
When I do this, I do see a corresponding change in the request:
<- "DELETE /feeds/api/users/[USER_ID]/uploads/[VIDEO_ID] HTTP/1.1\r\nAccept: */*\r\nUser-Agent: Ruby\r\nContent-Type: application/atom+xml\r\nHost: gdata.youtube.com\r\nContent-Length: 275\r\n\r\n"
<- "Host=gdata.youtube.com&GData-Version=2&Content-Type=application%2Fatom%2Bxml&Authorization=Bearer+[ACCESS_TOKEN]&X-GData-Key=key%3D[DEVELOPER_KEY]"
However, I still get the exact same response from YouTube. Error 400, bad request. What the heck is going on here??

Answer 1

Of course, 10 minutes after asking my question, I find out the answer. I did not understand the distinction between the HTTP header fields and form arguments, which I don't feel so bad about since it's not explained anywhere either in the Ruby documentation on Net::HTTP or in the YouTube API. The reason I was confused was because for uploading a video, you can provide all the values like Authorization and Content-Type as form data, so the above approach from my question works fine. For deleting a video, you have to provide those values as part of the header, not form data. At least, that is now my understanding.
Anyway, in case anyone ever runs into this problem, this solved it for me:
req = Net::HTTP::Delete.new(url.path)
req['GData-Version'] = '2' # this syntax sets header fields & values
req['Authorization'] = "..."
req['X-GData-Key'] = "..."
req.content_type = 'application/atom+xml'
httpreq = Net::HTTP.new(url.host, url.port)
httpreq.use_ssl = true
resp = httpreq.start {|http| http.request(req) }
Another case where one explanatory sentence from the authors of the documentation would have saved two hours of wasted time. If I had a nickel...